First pictures of the flooded rail line in WA's outback

The Trans-Australian Railway was flooded a week ago after an unprecedented dumping of rain in the famously arid areas of the Nullarbor Plain.

A year's worth of rain fell in many areas in the remote south-east of WA as a weather system fuelled by tropical moisture from the north remained "parked" in the area for three days.

The Eyre Highway was also cut for several days by the inland flood but has since re-opened.

Freight operators and motorists between Norseman and Eucla have been told to "exercise extreme caution" with water still lying on some sections.

In the north of the state, the Victoria Highway between the Northern Territory and WA has re-opened for now but with ex-TC Megan crossing the Top of the Territory during the next few days that situation, and also the condition of the Stuart Highway, is likely to quickly change.

The key Trans-Australian Railway remains closed after sections of the line were submerged by floodwaters.

More than 200mm of rain fell on parts of south-east WA in the 24 hours to 9am on Tuesday, with March rainfall records tumbling for the Eucla and Goldfields districts.

Cocklebiddy on the Eyre Highway had 333mm for the week, more than the region's long-term annual average rain.

The Australian Rail Track Corporation said work crews are still identifying repairs needed after the flood waters receded between Kalgoorlie and Rawlinna.

"Prolonged and intense rain in the area is impacting our ability to access all locations of the rail line and commence recovery efforts," ARTC said in a statement.

"While our crews have observed water levels subsiding in some locations, there are still a number of sites significantly impacted with water over the track.

"Given the current weather outlook, the best case scenario, with all flood waters receding would allow us to reopen the line towards the back end of next week," ARTC said on Friday.

"This will be reassessed as flood levels drop and as essential repairs are undertaken to damaged track and ballast, when it is safe for our crews to access."

The planned departure of the Indian Pacific from Perth last week was cancelled.

Operators, Journey Beyond Rail, had hoped to re-open for services on Sunday.

"We are monitoring the severe weather incident on the Nullarbor," the operator said on the weekend.

"Guests travelling on the Indian Pacific will be contacted via email and will also be phoned if this impacts your scheduled journey."

The Trans-Australian Railway spans 1693km of Australia's normally driest and most isolated terrain.

A national emergency as triggered when the line was cut at Tarcoola in the SA outback in July 2022 and required weeks to repair.

The difference this time is that the rail line from Adelaide splits at Tarcoola to head west across the Nullarbor, and north for Darwin, so both lines were out of action for some time.